Chasing top HIV players, Merck scores FDA approval for 2 new drugs

Merck secured FDA approval for two new HIV drugs on Thursday, two months ahead of the FDA's target action date for the meds. (Merck)

After marquee HIV drug approvals last year for Gilead and GlaxoSmithKline, Merck will follow into the crowded market with two new meds. The drugmaker scored FDA approvals for a new non-nucleoside reverse transcriptase inhibitor called doravirine, both alone and in a combo with other HIV therapies.

Merck’s Delstrigo and Pifeltro won FDA approvals to treat adult patients with HIV-1 who haven’t had prior antiretroviral treatments, the company reports. Delstrigo, a combo of doravirine plus older HIV drugs from Glaxo’s ViiV Healthcare and Gilead, carries a boxed warning about risks of worsening hepatitis B infections. 

Pifeltro contains only doravine, and is to be administered with other antiretroviral drugs. Speaking on a recent conference call, Merck's president of global human health Adam Schechter said doravirine is a “near-term way for us to continue to be relevant in the market but a real growth opportunity as we bridge into the future with our pipeline.”  

Merck’s George Hanna, VP and therapeutic area head of infectious diseases, said in a statement the drugs “offer a compelling clinical profile for clinicians and people living with HIV.” The approvals come nearly two months ahead of the FDA's target action date; the drugs should be available within a month, Merck said.

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GlobalData senior pharma an analyst Thomas Moore said in a statement the new drugs should be "well received" by doctors. The firm predicts the meds will pull in a combined $500 million in sales in 2023. Delstrigo costs $70 per day, while Pifeltro costs $46 per day, according to GlobalData. Moore said that Delstrigo comes in at the lower end the price range for three-drug combos, which tend to cost $70 to $80 per day.

"Merck will be hoping that this pricing strategy will give them a competitive edge over products from other companies in the HIV space, such as Gilead’s Genvoya and ViiV’s Triumeq, which are sold towards to top end of this price range," he added.

Behind these meds, Merck has a nucleoside reverse transcriptase translocation inhibitor in development called MK-8591. In preclinical trials, the drug inhibited HIV reverse transcriptase through mechanisms that are “different from any approved” HIV drugs, Merck reports.

The two newly approved drugs are taken once daily and enter a crowded market. Notably, last year Gilead won approval for its blockbuster-to-be Biktarvy, while GlaxoSmithKline’s ViiV Healthcare unit picked up an important nod for Juluca. 

Analysts have predicted Gilead’s Biktarvy will generate megablockbuster sales, with consensus estimates at around $6 billion in 2025. The team at Leerink sees even more potential in the med, and predicted Biktarvy's sales will reach $10 billion that year.  

Juluca, a combo of GSK’s Tivicay and Johnson & Johnson’s Edurant, carries more modest expectations, according to analysts. Jefferies’ Jeffrey Holford previously predicted the med would bring in £321 million ($426 million) in 2021. But Glaxo is also working on a follow-up combo of its meds Tivicay and Epivir that Jefferies analyst Ian Hilliker believes could pull in blockbuster sales, according to a note from June. 

Editor's note: This story was updated with analyst comments.